皇甫川流域中国沙棘树干液流日变化及其相关因子

Diurnal variation of Hippophae rhamnoides L. subsp. sinensis Rousi stem sap flow in Huangfuchuan Basin and related environmental factors

运用热耗散(TDP)法对皇甫川流域中国沙棘(Hippophae rhamnoides L. subsp. sinensis Rousi)的树干液流速率进行测定,用自动气象站同步连续监测太阳总辐射、空气温度、空气相对湿度、风速、10 cm处土壤温度等环境因子,用LI-6400系列光合仪同步测定每日6:00—18:00的沙棘叶蒸腾速率。结果表明:非降雨时段,沙棘树干液流速率日进程变化呈现明显的昼高夜低的起伏趋势,白天液流速率变化有波动,夜间液流速率变化缓慢;降雨时,在降雨的开始时段,沙棘树干液流速率明显增大,降雨中后期,液流速率明显减小并趋于平缓;以环境因子作自变量,以单位叶干质量的液流量为因变量,经过逐步回归,建立了多元线性模型,回归方程显著。

The sap flow rate of Hippophae rhamnoides L. subsp, sinensis Rousi in Huangfuchuan Basin was measured by using thermal dissipation probe method, and the related environmental factors such as incident solar radiation, air temperature, relative air humidity, wind speed, and soil temperature at the depth of 10 cm were recorded continuously by using automatic weather station. At the same time, the leaf transpiration rate during 6：00-18：00 was also measured by LI- 6400. The results showed that in the period of no rainfall, the sap flow rate of H. rhamnoides varied regularly, with higher value in daytime than in nighttime and more apparent fluctuation in daytime than in nighttime. The sap flow rate increased significantly at the beginning of rainfall, but after then, it descended and became steady. Taking the incident solar radiation, air temperature, relative air humidity, wind speed, and soil temperature at the depth of 10 cm as independent variables and the sap flow flux per unit dry foliage mass as dependent variable, a multiple linear equation was established by stepwise regression, and the regression was significant.